ON MILK AND MILK-TESTING 7I 



What are the different forms of adulteration of 

 milk often found? 



1. Watering. 



2. Skimming. 



3. Watering and skimming. 



4. The addition of preservatives. 



5. Addition of coloring matter. 



6. The addition of acid neutralizers. 



How does watering affect the percentage of the 

 different milk solids? 

 It reduces the percentage of all the milk solids, 

 and reduces them in the same proportion. 



How does skimming affect the percentage of the 

 milk constituents? 



It reduces the percentage of the fat and slightly 

 increases the percentage of all other constituents. 



How may the presence of added water in milk be 

 determined? 



Since the water of milk has the same chemical 

 composition as pure water from any source, and 

 the water content of milk varies to some extent, the 

 presence of added water in small amounts cannot 

 be determined directly. When the low lactometer 

 reading, low fat content, or physical characteristics 

 of the milk lead one to suspect that it is adulter- 

 ated a control sample of the milk as produced by 

 the cow or herd should be procured if possible. The 

 composition of the two samples should be com- 

 pared. If the suspected milk is to any great extent 

 lower in quality, and especially if the per cent of 



